This invention is directed to a new and improved electrical interconnector system and method of making same in order to couple terminals at the edge of a liquid crystal package, integrated circuit array circuit board or the like to a circuit board, integrated circuit array or the like.
Liquid crystal packages have begun to gain prominence in many applications as for example, as a display for digital watches. See the magazine THE ELECTRONIC ENGINEER, November, 1972, pages 70-72 published by the Chilton Company, Philadelphia, Pa.
Such liquid crystal packages have in the past been generally coupled to the circuit board containing elements for controlling the liquid crystals via wires soldered between the circuit board and the terminal of the liquid crystal package.
Although this method is quite adequate it does suffer disadvantages in that soldering is expensive and replacement of the circuit board or the liquid crystal package is most difficult in that the wires must be unsoldered. In addition, failure may occur due to shock or vibration causing an electrical disconnect.
Other types of interconnectors using conductive plastic have been reported in the art (for example, see U.S. Pat. Nos. 3,818,279 and 3,861,136) but they suffer disadvantages in that they are difficult to inexpensively manufacture in volume quantities while still maintaining the necessary reliability needed in many applications.
In addition, the fold-over scheme shown in FIG. 9 of U.S. Pat. No. 3,818,279 has not always proved reliable since folding the conductive plastic strips on a single surface as shown causes portions being bent over to stretch and thus causes separation in the conductive particles carried in the strips. Separation of the particles causes a substantial increase in resistance of the strip and thus is in some cases no longer usable for its intended purposes.
Reference may also be had to U.S. Pat. Nos. 3,680,037, 3,620,873, 3,670,205 and 3,434,401 for a better understanding of the art of interconnectors.
In view of the foregoing a new and improved method was needed for constructing interconnectors overcoming the disadvantages of the prior art. In addition, a new and improved reliable interconnector was needed which has thin conductive connecting plastic strips positioned and supported around corners of an insulator support.
Thus the present invention in one aspect provides an interconnector in which conductive plastic strips are bonded about corners of an underlying insulator support. Thus, rectangular, triangular and other cross-sectional shaped interconnectors can now be reliably produced.
In another aspect this invention provides a new and improved method for transferring conductive plastic strips to an insulator support to form the improved interconnector.
The improved method now permits reliable bonding of conductive plastic segments around corners between or joining two surfaces e.g., two surfaces which if carried forward intersect at an angle .alpha. between about 30.degree. to 135.degree. and more preferably 60.degree. to 120.degree. (see FIG. 2). FIG. 2 particularly discloses an angle .alpha. of about 90.degree..
In a further aspect this invention provides a new and improved interconnector having inlaid conductive strips which extend to top, side and bottom surfaces (see FIG. 2) and which are at least partly exposed to permit electrical contact therewith.
In yet another aspect of this invention there are provided preformed conductive plastic strips which are bonded to and about surfaces of an insulator support as well as a new and improved method for bonding said strips to said support.
It should be understood that as used herein the term corner is meant to include a corner which may be rounded off.